1. Field of the Invention
The present invention relates generally to a method for casting an elongated continuous metal strip and an apparatus, a so-called "belt-caster", capable of carrying out the method. More particularly, the invention relates to a method and apparatus for casting an elongated continuous metal strip from molten metal and which provides a relatively high yield.
2. Description of the Prior Art
Japanese Patent First Publication No. (Tokkai) Showa 59-153553 discloses an apparatus for casting an elongated continuous metal strip. This conventional casting apparatus has a pair of endless belts which define a casting chamber together with side walls covering the lateral edges of the casting chamber. Molten metal is supplied to the casting chamber via an inlet and driven toward the outlet of the casting chamber continuously by means of pinch rollers downstream of the belts. As the metal travels toward the outlet, the belts and the side walls of the casting chamber cool the metal into an elongated, continuous, thin metal strip or plate.
During this casting process, the side walls tend to retard the movement of the solidifying metal in the casting chamber. The resulting friction exerts stress on the metal passing through the casting chamber. Since the metal is still only partially solidified, this friction may cause the metal strip to shear across its width, resulting in a disastrous interruption of the continuous feed commonly called "break-out". Naturally, this will occur any time the feeding force fails to overcome the frictional force. Sticking of the solidified metal onto the opposing surface of the side wall may also cause this kind of friction.